Thin him transistor-liquid crystal displays (TFT-LCDs) have the characteristics of small size, low power consumption, relatively low manufacturing cost, non-radiation and the like, thereby prevailing in the current flat panel display (FPD) market.
Currently, the display mode of the TFT-LCDs mainly includes twisted nematic (TN) mode, vertical alignment (VA) mode, in-plane-switching (IPS) mode and advanced super dimension switch (AD-SDS, also referred to as ADS) mode.
The operating principles of an ADS mode liquid crystal display (LCD) are mainly as follows: a multidimensional electric field is formed with an electric field generated between edges of slit electrodes in the same plane and an electric field generated between a slit electrode layer and a plate electrode layer, so that liquid crystal molecules at all orientation between the slit electrodes in a liquid crystal cell and above the electrodes can rotate, and thus the operating efficiency of liquid crystals can be improved and the light transmission efficiency can be improved as well. By adoption of the ADS technology, the picture quality of TFT-LCD products can be improved. Moreover, the TFT-LCD products have the advantages of high resolution, high transmittance, low power consumption, wide viewing angle, high aperture ratio, low color difference, no push Mura and the like.
A conventional ADS mode TFT-LCD array substrate generally comprises a group of gate lines and a group of data lines which are vertically intersected with the gate lines; a pixel region (pixel unit) is defined by a gate line and a data line which are intersected with each other. As illustrated in FIG. 1 which is a cross-sectional view of the pixel region at a thin film transistor (TFT), each pixel region comprises a gate electrode 11 formed on a substrate 10, a gate insulating layer 12, an active layer 13, a source electrode 15, a drain electrode 16, a pixel electrode 14 (plate electrode), a passivation layer 17, and a common electrode 18 (slit electrode); the common electrode 18 is provided with a plurality of slit structures 181 and a plurality of electrode strips 182; and the TFT is constituted with the gate electrode 11, the gate insulating layer 12, the active layer 13, the source electrode 15 and the drain electrode 16.
In the process of manufacturing the array substrate, one mask patterning process is required for forming each of the pattern of the gate electrode and the gate line, the pattern of the active layer, the pattern of the source electrode, the drain electrode and the data line, the pattern of the pixel electrode, and the pattern of a through hole. Thus, the ADS mode TFT-LCD array substrate as illustrated in FIG. 1 can be formed by the mask patterning process for 1+5 times.
In particular, the pattern of the active layer and the pattern of the pixel electrode are respectively formed by one mask patterning process. In addition, each mask patterning process includes a plurality of steps. Therefore, the manufacturing process of the conventional array substrate is complicated and the productivity is difficult to improve.